The invention relates to a DC/DC converter having an input and an output, a longitudinal arm arranged between the input and the output, in which at least a first inductor and a first capacitor are arranged, and a capacitor arranged in a first shunt arm at the output, and another shunt arm with different arrangements of a second inductor and two switches.
In many areas of technology it is necessary to convert an available DC voltage to operate connected loads. Such a conversion of an available so-called supply input voltage Ue can be performed, for example, with a DC/DC converter, wherein the DC/DC converter can generate for the connected loads an output voltage Ua which is smaller or larger than the input voltage Ue.
Such DC converters find application, for example, in machines or industrial plants, in a variety of electronic devices and in vehicle manufacturing. For example, such DC converters are customary in so-called switching power supplies, which are often used in computers, notebooks, mobile phones, hi-fi devices and small motors.
The advantages of such converters are improved efficiency and reduced heat generation.
To convert the electrical energy, so-called clocked converters are typically used as DC/DC converters, which are controlled with a control signal, which determines the clock signal for switching the single switch arranged in the converter. Customarily, one or more passive electrical storage devices, such as capacitors and/or inductors, are arranged in such converters. The operating principle for converting an input voltage into an output voltage is a controlled cyclic charging and discharging of the passive electrical storage devices.
For example, active, electrical semiconductor switches such as a BJT (Bipolar Junction Transistor), a MOSFET (Metal-Oxide-Semiconductor Field-Effect-Transistor) or an IGBT (Insulated Gate Bipolar Transistor) are used instead of a switch required in the DC/DC converter.
The result at the input and/or output of power controller is a triangular current curve or voltage curve due to the cyclic charging and discharging of the passive electrical storage devices, such as capacitors and/or inductors. This effect is also referred to as ripple and represents an alternating current of an arbitrary frequency and waveform superimposed on a direct current. Also used is the concept of a pulsating direct current.
These high-frequency ripples generate harmonics which cause disturbances in other connected electronic components. To limit these interfering electromagnetic fields, attempts are generally made to attenuate the ripple by using larger or additionally employed components. Such approaches can be found in “A ‘Zero’ Ripple Technique Applicable To Any DC Converter” David C. Hamill, Surrey Space Center, University of Surrey, Guildford, UK, d.hamill@surrey.ac.uk and in Ripple Steering AC-DC Converters to Minimize Input Filter, Eric CHOU, Frank CHEN, Claudio Adragna, Bruce LU.
Furthermore, ideas have been proposed to reduce ripple by additional active sources, as disclosed in Techniques for Input Ripple Current Cancellation: Classification and Implementation, N. K. Poon, J. C. P. Liu, C. K. Tse and M. H. Pong. Alternatively, modifications to minimize disturbances with coupled inductors are also known from AN3180, Application Note, A 200 W ripple-free input current PFC pre-regulator with the L6563S, © 2010 STMicroelectronics.